Light fixture

ABSTRACT

A light fixture in which the non-electrical end of a lamp is held by a socket having heat insulating and cushioning surfaces arranged in a generally conical pattern.

United States Patent Landrum et al.

LIGHT FIXTURE Inventors: Leon L. Landrum, Houston; Robert L. Holder, Nacogdoches, both of Tex.

Assignee: Esquire, lnc., New York, NY.

Notice: The portion of the term of this patent subsequent to Dec. 25, 1990, has been disclaimed.

Filed: Aug. 29, 1973 Appl. No.: 392,496

Related US. Application Data Division of Ser. No. 199,232, Nov. 16, 1971, Pat. No. 3,781,539.

US. Cl. 240/52 R; 240/52 R Int. Cl. F2lv 21/00 Field of Search 240/3, 52 R, 90, 41 BM,

[ *OCL 7, 1975 [56] References Cited UNITED STATES PATENTS 2,727,137 12/1955 Oharenko 240/90 3,071,681 l/1963 Schmidt et 211... 3,168,986 2/1965 Jeffree et a1. 3,358,133 12/1967 Thoman et a1... 3,610,915 10/1971 Moore 3,666,934 5/ 1 972 Moore 3,781,539 12/1973 Landrum et a1. 240/52 R Primary ExaminerFred 1... Braun Attorney, Agerit, or Firm-W. F. l-lyer; Marvin B. Eickenroht [5 7] ABSTRACT A light fixture in which the non-electrical end of a lamp is held by a socket having heat insulating and cushioning surfaces arranged in a generally conical pattern.

3 Claims, 11 Drawing Figures U.S. Patent Oct. 7,1975 Sheet 1 of3 3,911,265

U.S. Patent 0a. 7,1975 Sheet 2 of3 3,911,265

U.S. Patent Oct. 7,1975 Sheet 3 of 3 3,911,265

LIGHT FIXTURE This is a division of Application Ser. No. 199,232, filed Nov. 16, 1971, now US. Pat. No. 3,781,539.

This invention relates generally tolight fixtures and parts thereof. More particularly, it relates to improvements in fixtures of the type in which the non-electrical end of a lamp is engaged so as to hold the lamp in proper alignment with a reflector and prevent it from being broken due to jars and vibrations.

As noted in US. Pat. No. 3,001,060, which is assigned to the assignee of the present invention, light fixtures of this type are especially useful at industrial locations, where the lamps are large and heavy and often subjected to such jars and vibrations. In accordance with such patent, a socket having a cylindrical heat insulating and cushioning surface was mounted in the housing of the fixture for fitting closely over a similarly shaped protuberance on the non-electrical end of a metal halide typelamp known in the art as a Bulged Tubular or BT.

Although the light fixture of US. Pat. No. 3,001,060 represented a substantial improvement over the prior art, the cylindrically shaped heat insulating and cushioning surface of its socket was not well suited for holding the non-electrical end of another metal halide type lamp known in the art as an Elliptical or E. As its name implies, the non-electrical end of this type lamp is elliptically shaped, and, in accordance with US. Pat. No. 3,284,621, which is also assigned to the assignee of the present invention, it was proposed to hold such a lamp by means of a pin having a heat insulating and cushioning surface for fitting closely within a recess or dimple in the non-electrical end thereof.

In accordance with US. Pat. No. 3,459,934, also assigned to the assignee of the present invention, a light fixture was provided with means for alternately holding either a BT" lamp or an E lamp. Thus, as shown in this latter patent, a button having an external heat insulating and cushioning surface and a socket having an internal cylindrical heat insulating and cushioning surface were so arranged within a housing that either could be selectively moved into and out of operative positions for engaging the non-electrical end of one such lamp.

In the fixtures illustrated in each of the foregoing patents, the electrical socket is releasably secured across an access opening into the housing of the fixture to permit relamping. Thus, the non-electrical end of the lamp is moved into engagement with the socket or button for holding it as the electrical socket is moved into secured position. In accordance with the light fixtures illustrated in US. Pat. No. 3,610,915, and pending application, Ser. No. 815,003, filed Apr. 10, 1969, now US. Pat. No. 3,666,934 both of which are also assigned to the assignee of the present application, it is proposed to permit relamping without removal of the electrical socket, by permitting either or both of the electrical socket and non-electrical socket for engaging the opposite end of a lamp to be adjusted in a direction axially of the wall of the fixture on which its mounted to enable the lamp to be moved into and out of positions between them.

For this purpose, the lamp is preferably tilted to a position in which, its electrical end may be moved substantially axially into the electrical socket, and then swung into a position in which its non-electrical end is axially opposite the non-electrical socket, after which the sockets may be moved relatively toward one another so as to hold the lamp therebetween. However, although providingimprovements overthe fixtures of the prior patents in this respect, these latter fixtures nevertheless are adapted to hold only one type of lamp in this case, a BT" type. Thus, in the interest of reducing the required relative axial movement between the sockets, and thus the wall-to-wall spacing within the housing, the non-electrical socket is relatively shallow and thus particularly ill suited for holding an E type lamp.

An object of this invention is to provide a light fixture having a socket which is also adapted to hold the nonelectrical ends of these different types of lamps, but which does not require dual, alternatively usable lamp engaging parts, and, in its preferred embodiment, does not require that either socket be removed from the fixture housing in order to relamp.

Another object is to provide such a light fixture having a non-electrical socket which is of such construction that it interferes to only a small extent with maximum transmission of light from the lamp.

A further object is to provide such alight fixture of this type which enables a lamp to be installed or removed from between it and an electrical socket with a minimum amount of relative movement therebetween, and thus with minimum wall-to-wall spacing requirements within the fixture housing.

These and other objects are accomplished, in accordance with the illustrated embodiments of this invention, by a light fixturehaving a non-electrical socket which provides heat insulating and cushioning surfaces which diverge outwardly toward the electrical socket and in a generally conical pattern arranged axially thereof. Thus, the surfaces of the non-electrical socket are adapted to engage and hold any one of a cylindrically shaped end of a BT lamp, an elliptically shaped end of an E lamp, or the spherically shaped end of a Tubular or T metal halide type lamp.

In the illustrated and preferred embodiments of the invention, the sockets are mounted on oppositely facing walls of the housing, and-are caused to move relative to one another by means for moving at least one of them toward and away from the wall on which its mounted. In this way, the lamp may be inserted between, and conversely removed from between, the sockets upon movement of at least one of them toward and away 8from the wall on which it is mounted, thereby avoiding the necessity of removing the socket from the housing.

The heat insulating and cushioning surfaces of the non-electrical socket are circumferentially discontinuous to form at least one generally V shaped opening in the side of the socket whose edges are circumferentially spaced apart an angle of less than one hundred eighty degrees. In this manner, the non-electrical end of the lamp may be moved into and out of alignment with the non-electrical socket by passing through wide portions of the V shaped opening, so that the socket need not be moved away from the electrical socket a distance as great as the axial depth of the socket. Furthermore, the body of the socket upon which the heat insulating and cushioning surfaces are supported may be of smaller size and weight, and'permits more light to be transmitted from the lamp than would be possible in the event the conical surfaces were circumferentially continuous.

More particularly, the socket body includes two or more circumferentially equally spaced-apart fingers having adjacent side edges circumferentially spaced apart angles of less than three hundred sixty degrees divided by the number of such fingers. The illustrated and preferred socket has three relatively narrow fingers, with their adjacent edges being now substantially less than one hundred twenty degrees apart, so as to provide relatively wide openings through which the non-electrical end of the lamp will pass, and at the same time provide the firm engagement inherent in a three point support.

In the drawings, wherein like reference characters are used throughout to designate like parts:

FIG. 1 is a perspective view of a light fixture having a BT type lamp mounted therein in accordance with the present invention;

FIG. 2 is an enlarged view, partly in section, of the non-electrical socket of the fixture separated from its mounting on one end wall of the housing;

FIG. 3 is a front view of the fixture, with the nonelectrical socket moved to the left to permit insertion of a lamp between it and the electrical socket;

FIG. 4 is a view similar to FIG. 3, but during insertion of the lamp;

FIG. 4A is an enlarged sectional view of the nonelectrical socket upon movement of the non-electrical end of the lamp between its adjacent fingers;

FIG. 5 is another front view of the fixture, with the non-electrical socket moved to the right into engagement with the non-electrical end of the lamp;

FIG. 6 is another front view of the fixture, but upon retraction of the non-electrical socket to permit insertion of an E lamp between it and the electrical socket;

FIG. 7 is a view similar to FIG. 6, but upon movement of the non-electrical socket to the right into engagement with the non-electrical end of the E lamp;

FIG. 8 is another front view of the fixture, but with a T" type lamp held between its electrical and nonelectrical sockets;

FIG. 9 is a view similar to FIG. 8, but upon movement of the non-electrical socket to the left and out of engagement with the non-electrical end of the T lamp; and

FIG. 10 is another front view of the fixture, during removal of the T lamp from between its sockets.

With reference now to the details of the abovedescribed drawings, the fixture best shown in FIG. 1, and indicated in its entirety by reference character 10, includes a housing 11 having oppositely facing side walls 12 and 13, upper and lower walls 14 and 15, and a window 16 in its front end. The window is closed by a pane 17 of glass carried by a frame 17A releasably attached in any suitable manner across the front end. The fixture housing 1 1 may be mounted. by supports 18 for swinging about a horizontal axis so as to reflect light in a desired direction through the window.

A reflector 19, which is curved both horizontally and vertically, is mounted within the housing with its concave side spaced from and facing the window 16. An electrical socket 20 is mounted on the right side wall 13 and a non-electrical socket 21 is mounted on the left side wall 12 of the housing in generally axially aligned relation with one another. More particularly, the sockets 20 and 21 extend through holes 22 and 23, respectively, in opposite sides of the reflector for engaging the Opposite ends of a BT lamp 24 so as to hold it firmly in position between the reflector and the window. More particularly, the lamp is so held with the center of its line source of light coinciding with the focal center of the reflector 19, whereby a symmetrical pattern of light is reflected through the window 16. v

The electrical socket 20 is of conventional construction including the usual ceramic sleeve 25 secured to the wall 13 and having threads 26 therein to receive threads 27 on the electrical end of the lamp 24. Thus, as well known in the art, in the making up and breaking out of such threads, the electrical end of the lamp is moved axially into and out of the sleeve 25 to engage and disengage its threads with threads 26. As also well known in the art, the sleeve is of such size as to permit the lamp end to be moved into and out of it when the lamp is angled or cocked.

As best shown in FIG. 2, the non-electrical socket 21 comprises a body 28, which may be a metal casting, having a base or tubular extension 29 and three fingers 30 diverging from the right end of the tubular extension. As previously described, the socket 21 is mounted on the side wall 12 of the housing for moving axially toward and away from the electrical socket 20. Thus, a threaded pin 31 is mounted on the wall 12 for extension inwardly therefrom to receive threads 32 in the left end of the tubular extension 29. As best shown in FIG. 2, the pin 31 is mounted on housing wall 12 by means of a plate 33 secured to raised portions 34 on the wall 12 by means of screws 35. More particularly, the pin 31 extends through and is adjustably located with respect to the plate by means of lock nuts 36 engaging opposite sides of the plate.

As previously described, and as will be apparent from FIG. 2, the fingers 30 of the socket 21 extend at equal angles with respect to the axis of the tubular member 29 so that their inner faces are arranged in a conical pattern coaxial with the socket 20. More particularly, the fingers are relatively narrow, of the same length, and generally equally circumferentially spaced apart, so that their adjacent side edges form .V shaped openings therebetween which subtend openings of only slightly less than one hundred twenty degrees. The circumferentially discontinuous inner faces of the fingers 30 are covered with a heat insulating and cushioning material 37, such as asbestos.

As illustrated in FIG. 4, in order to install the lamp 24, the framed glass is removed from window 16 to receive the lamp therethrough, and the non-electrical socket 21 is moved axially over the pin 31 to the left, as shown in FIG. 3. Thus, the lamp may be tilted somewhat into a position in which its electrical end may be inserted into and made up with threads 26 on the socket 20. As the threads are so made up, the lamp is swung into a position axially aligned with the sockets and thus with its non-electrical end opposite the socket 21.

As illustrated in FIG. 4A, the protuberance on the non-electrical end of the BT lamp 24 is adapted to pass between adjacent fingers 30 on the socket 21 as it is so swung into alignment with the electrical and nonelectrical sockets. Thus, its not necessary to back the socket off an axial distance as great as would be required, for example, if the conical surfaces of the socket 21 were circumferentially continuous. At the same time, of course, the pin 31 is so mounted on the wall 12 that its free end will be out of the way of the non-electrical end of the lamp 24 as the lamp is swung I into alignment with the electrical and non-electrical sockets.

As illustrated in FIG. 5, when the electrical end of the lamp 24 has been fully made up with the socket 20, the non-electrical socket 21 may be moved over the pin 31 to the right so as to bring the heat insulating and cushioning material on the inner faces of the fingers into firm engagement with the protuberance on the end of the lamp. As will be understood, the three point engagement of the socket with the lamp inherently provides a firm and balanced support, and the narrow fingers reduce to a minimum the size of casting 28. Still further, the openings 30 permit a maximum of light to be transmitted from the end of the lamp engaged by the socket.

Obviously, removal of the lamp 24 for relamping purposes merely involves a reversal of these procedures above described. That is, window 16 is opened to permit the non-electrical socket 21 to be backed off to the extent necessary to permit the non-electrical end of the lamp to be moved between its fingers, and the threads on the electrical end of the lamp are backed outof those of socket 20 as the lamp is swung into the tilted position of FIG. 4.

In FIG. 6, the socket 21 has been moved to the left to approximately the position shown in FIG. 3 to permit installation of an E type lamp 24A. Thus, the lamp has been tilted to permit the threads on its electrical end to make up with those of the socket 20 and the elliptically shaped non-electrical end thereof to be moved between adjacent fingers of the socket 21. Ordinarily, the extent to which the socket must be backed off to permit installation of this type of lamp will be about the same as that required in order to install a BT type lamp, as previously described. As shown in FIG. 7, upon disposal of the lamp in axial alignment with the sockets, the socket 21 has been moved to the right to cause its heat insulating and cushioning surfaces to firmly engage the end of the lamp 24A.

As previously described, the metal halide lamp 24B shown installed between the electrical and nonelectrical sockets in FIG. 8 is a Tubular or T type. In order to remove this lamp 24B from its installed position, the socket 21 is first backed off or moved to the left, as illustrated in FIG. 9, to a position in which the spherically shaped non-electrical end of the lamp 24B may be moved through one of the V shaped openings between adjacent fingers of the socket 21. Ordinarily, this will be approximately the same distance that is required in permitting installation or removal of the BT and E lamps illustrated in FIGS. 1 to 7.

At any rate, when the socket has been backed off to this extent, the threads on the electrical end of the lamp 24B may be backed off from the threads of the electrical socket 20 a distance sufficient to permit the nonelectrical end of the lamp to be tilted somewhat, as shown in FIG. 10, for movement between the V shaped opening as the threads on the lamp are fully removed from the threads on the electrical socket.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed 1. A socket for use in engaging the non-electrical end of the lamp mounted in the housing of a light fixture, comprising a body having a tubular base having means on one end providing heat insulating and cushioning surfaces which diverge outwardly therefrom in a generally conical pattern, and internal threads adapted to receive a threaded pin on a wall of the housing in order to mount said heat insulating and cushioning surfaces in a position to engage and move axially toward and away from the non-electrical end of the lamp.

2. A light fixture, comprising a housing, a first socket in the housing for receiving the electrical end of a lamp, a second socket in the housing including a tubular base and means providing heat insulating and cushioning surfaces which diverge outwardly in a generally conical pattern from one end of the tubular base, a pin on the housing telescopically arranged within the tubular base to mount said base of the second socket coaxially of the first socket, and the insulating and cushioning surfaces in position to engage the opposite end of the lamp when its electrical end is received by said first socket, and permit said second socket to be moved axially toward and away from the first socket, and means on said tubular base and pin which are engageable with one another to permit the second socket to be held in a desired axial position relative to said first socket.

3. A light fixture of the character defined in claim 2, wherein the engageable means comprises threads on the pin and tubular base. 

1. A socket for use in engaging the non-electrical end of the lamp mounted in the housing of a light fixture, comprising a body having a tubular base having means on one end providing heat insulating and cushioning surfaces which diverge outwardly therefrom in a generally conical pattern, and internal threads adapted to receive a threaded pin on a wall of the housing in order to mount said heat insulating and cushioning surfaces in a position to engage and move axially toward and away from the nonelectrical end of the lamp.
 2. A light fixture, comprising a housing, a first socket in the housing for receiving the electrical end of a lamp, a second socket in the housing including a tubular base and means providing heat insulating and cushioning surfaces which diverge outwardly in a generally conical pattern from one end of the tubular base, a pin on the housing telescopically arranged within the tubular base to mount said base of the second socket coaxially of the first socket, and the insulating and cushioning surfaces in position to engage the opposite end of thE lamp when its electrical end is received by said first socket, and permit said second socket to be moved axially toward and away from the first socket, and means on said tubular base and pin which are engageable with one another to permit the second socket to be held in a desired axial position relative to said first socket.
 3. A light fixture of the character defined in claim 2, wherein the engageable means comprises threads on the pin and tubular base. 